Relay system



April 9, 1929.

c. w. STONE 1,708,806

RELAY SYSTEM Filed Dec. 29, 1923 InVentor Charles \X/. Stone, y

His Attorney.

Patented Apr. 9, 1929.

UNITED earns rsr orrics.

CHARLES W. STONE, OE NISKAYULNA, NEW YORK, AS'SIGNOR T0 GENEfiAL ELECTRIC COMPANY, A. CORPORATION OF NEW YORK.

RELAY SYSTEM.

Application filed December 29, 1923. Serial No. 683,512.

My invention relates to relay systems, and has for its object the provision of a relay device operable in response to change in frequency of the voltage impressed on it.

It is frequently desirable to control the connection of one or more electric circuits in accordance with change in the frequency of a voltage impressed either on the controlled circuits or on another circuit associated therewith. Control by variation in frequency, however, involves certain difiiculties when the frequencies used are comparatively high because of the unsatisfactory operation of a coil operated switch, the operating coil of which constitutes a high and variable reactance in the high frequency circuit. In order to avoid these difiiculties, I provide an arrangement for operating one or more switches by unidirectionalcurrent of a value determined by the frequency of the circuit from which current for actuating the switch or switches is supplied.

My invention will be better understood on reference to the following description when considered in connection with the accompanying drawing and its scope will be pointed out by the appended claims.

Referring now to the drawing, the single figure thereof shows a switch 1 arranged to control the connection of a circuit 2 and provided with an operating coil 8 to which current may be supplied from a line 4 through transformer 5 and rectifier 6 which is connected in one of the connections between the transformer and coil. The rectifier 6 comprises an evacuated vessel 7 containing a filament cathode 8 and a plate anode 9 arranged to cooperate therewith. The condenser 10 and reactanjce coil 11 together with the secondary winding 12 of the transformer 5 form a series resonant circuit by means of which the value of the filament current and consequently that of the rectified current supplied to the coil 3 may be controlled in accordance with the frequency of the voltage impressed on the primary winding 13 of the transformer 5.

The circuit'comprising the condenser 10, the coil 11 and the winding 12 may of course be tuned for resonance at any desired frequency. When the line 4 is operating at a frequency below the resonance frequency of the tuned circuit, the current supplied to. the coil 3 is insufiicient to operate the switch 1. As the frequency of the line 4: is increased,

however, the heating current of the filament 8 increases until at resonance frequency, or frequencies near the resonance frequency, sufficient current for operating the switch 1 is supplied. At frequencies in excess of the resonance frequency the current supplied to the coil 3 is reduced to a value insufficient to operate the switch 1. My invention thus affords an effective means for controlling a switch or other device in accordance with the frequency of the voltage impressed on the control circuit. Relay devices of this character are capable of many different applications among which may be mentioned the selective control through a single control circuit of a plurality of different switches or other devices, relays tuned to different frequencies being utilized to control the operation of the separate devices in response to change in frequency of the voltage impressed on the control circuit.

My invention'may be embodied in many other forms than that shown and described. I, accordingly, do not wish to be restricted to the particular form of construction disclosed herein by way of example for the purpose of setting forth my invention in accordance with the patent statutes. The

terms of the appended claims are, therefore, not restricted to the precise structure disclosed, but are intended to cover all changes and modifications within the spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent, is p 1. A relay system comprising a source of electricity, a device to be operated, hot

cathode rectifier for rectifying the current supplied from said source to said device, and a tuned circuit for controlling the heating of the cathode of said rectifier in accordance with the frequency of said source.

2. A relay system comprising a source of electricity, a switch to be operated in response to change in the frequency of said source, and a relay device including a hot cathode rectifier for rectifying the current supplied from said source to the operating coil of said switch and a series resonant circuit for controlling the heating current of said cathode in accordance with the frequency of said source. I

In witness whereof, I have hereunto set my hand this 28th day of December, 1923. CHARLES W. STONE. 

